ITM 301 MIDTERM
Lecture 1
Network Models
-
Topology
—How parts of a whole work together
-
Physical topology
—Mostly applies to hardware and describes how computers, other devices,
and cables fir together to form the physical network
-
Logical topology
—Has to do with software and describes how access to the network is
controlled
How users and programs initially gain access to the network
-
Network operating system (N O S)—
Controls access to the entire network
Required by client-server models
Peer-to-Peer Network Model
-Peer-to-peer (P 2 P) network model
—The O S of each computer on the network is responsible
for controlling access to its resources
No centralized control
-Computers, called nodes or hosts, form a logical group of computers and users
May share resources
May prevent access to resources
-Advantages
Simple configuration
Less expensive (compared to other network models)
-Disadvantages
Not scalable
Not necessarily secure
Not practical for large installations
Client-Server Network Model
-Resources are managed by the network operating system (N O S) via a centralized directory d-
database
-
Windows domain
—A logical group of computers that a Windows Server can control
-
Active Directory (A D)
—The centralized directory database that contains user account
information and security for the entire group of computers
-A user can sign on to the network from any computer on the network and gain access to the
resources that A D allows
-This process is managed by Active Directory Domain Services (A D D S)
ITM 301 MIDTERM
-Client
A computer making a request from another
-Clients don’t share their resources directly with each other
Access is controlled by entries in the centralized domain database
-Client computers access resources on another computer by way of the servers controlling the
domain database
-The N O S is responsible for the following activities:
Manages client data, resources
Ensures authorized user access
Controls user file access
Restricts user network access
Dictates computer communication rules
Supplies application to clients
-Server examples
Windows Server 2016, Ubuntu Server, or Red Hat Enterprise Linux
-Servers that have a N O S installed require:
More memory, processing, and storage capacity
Equipped with special hardware
o
Provides network management functions
-Advantages relative to peer-to-peer networks
User credential assigned from one place
Multiple shared resource access centrally controlled
Central problem monitoring, diagnostics, and correction capabilities
More scalable
Client-Server Applications
-
Network services
—The resources a network makes available to its users
Includes applications and the data provided by these applications
-
In client-server applications
A client computer requests data or a service from a second computer, called the server
-Protocols
Methods and rules for communication between networked devices
-Two primary protocols:
TCP (Transmission Control Protocol)
IP (Internet Protocol)
TCP/IP suite of protocols is used by OSs for communication on a network
